Since silicone resin has a water repellent characteristics, such silicone resin itself or its mixture with wax, silicone oil, lubricants or the like have been used as coating materials for various substrates exposed to the sea and which are liable to be damaged thereby, i.e. by the sea or sea life, e.g. plants, etc., which have deleterious effects on the coated substrates. However, in natural surroundings, the water repellent effect of such silicone resin gradually disappears and long lasting repellent effects cannot be expected, especially when exposed to the sea. Even when one attempts to recoat substrates coated with such silicone resin composition, there is the problem of inferior adhesion of the silicone resin composition to the previously applied silicone resin coating. For these reasons, none of the silicone based antifouling paints have been used practically on ships, submarine structures and the like. The reason why the antifouling effects of these paints cannot last long is believed as follows: Such active additives as wax, silicone oil, lubricant and the like are easily dissolved out in sea water and are leached from the coating in a comparatively short period of time. It is, therefore, an object of the invention to provide a novel silicone resin composition capable of forming a coating which is gradually hydrolyzed or decomposed at an appropriate speed in sea water, and which contains an active anti-fouling agent that is gradually released from the coated surface to prevent adhesion of the harmful sea life upon the coated surface. An additional object of the invention is to provide a novel silicone base coating composition which can form an effective and durable antifouling coat on ships, submarine structures and the like and which is excellent in recoatability. A further object of the invention is provide an attractive method for the preparation of such coating. Other objects of the invention shall be clear from the statements of this specification and claims.